Thomas henry blaie



(No Model.)

T. H. BLAIR.

PLATE HOLDER. Y

No. 294,959'. PatentedMar. ll, 1884.

lUnirse rares Parleur trice.

THOMAS HENRY BLAIR, OF BOSTON, MASSACHUSETTS, ASSIGNOB TO THE BLAIR TOUROGRAPH COMPANY, OF SAME PLACE.

PLATE-HOLDER.

SPECIFICATION forming part of Letters Patent No. 294,959, dated March 11, 1884.

Application filed January (l, 1883. Renewed February El, 1884. (No model.)

To @ZZ whom it may concern y Be it knownthat, Tiroims HENRY BLAIR, a citizen of the United States, residing at Boston, in the county vof Suffolk and State of 5 Massachusetts, lhave invented certain new and useful Improvements in Plate-Holders for Photographic Cameras; and I do hereby declare the following to be a l'ull, clear, and exact description of the invention, such as will 1o enable others skilled in the art to which it appertains to make and use the same, reference being had to the accompanying drawings,

and to letters or figures of reference marked thereon, which form a part of this specification.

This invention relates to double plate-hold ers of photographie cameras, and it consists in certain details of construction, as hereinafter explained.

The drawings accompanying` this specification represent in Figure l a side elevation, and in Fig. 2 an end view, of a plate-holder embodying my invention. Fig. 3 is a vertical and Fig. et a horizontal cross-section. Fig. 5 is a portion ot' asection'o' the plate-holder on line .t of Fig. l, and Fig. 6 on line i/ y-oi Fig. 5.

The body of my plate-holder is composed, first,of an open rectangular frame, A, contain- 3o ing in each of its. side edges, and centrally thereof, a longitudinal groove, c, these oppositelydisposed grooves being to inclose and slide upon ribs secured to or forming part oi' the camera-box. Heretof'ore double plate holders have been connected with or attached to cameraboxes by fastenings ot'such nature that the holder must be held in a certain position while being presented to and inserted in the catches which eonliue'it. By the em- 4o ployment ot' the parallel grooves a a, which are disposed midway between the two sides of the holder and the two plates contained in such holder, no precaution is necessary as to which side ot' such holder shall be uppermost, or

4 5 which position either end may bein.

plete the body of the plate-holder, employa central partition, B, which extends from side to side and end to end of the opening of the frame A, and is secured permanently to such frame in any suitable manner. Heretofore 5o this centrally-arranged partition B has been attached loosely or removably to the outlying frame A, for which reason it is liable to become misplaced during the insertion and removal of the plates. By Asecuring the parti- '55 tion B permanently or immovablyA to the frame A these objections are avoided.

The dark-slides77 of the holder are shown at O C as thin sheets of leather-board or other suitable material adapted to slide in grooves 6o b b, formedin inner opposite side edges of the frame A, upon each side the central iixed partition,B, the openings in the end ofthe frame by which such slides C C enterbeing shown at c c, and the chambers between the slides and partition for reception of the plates at B B.' To prevent accidental misplacement of the darkslides O O, and at the same time to allow them to be inserted either side outward, I add tothe outer end of each abar, D, of wood or other 7o material, of a thickness considerably greater than that of the slide, the edges of this bar extending an equal distance beyond each face of the slide, in order that the edge ot' this bar shall overlap the point between each slide C and the opening c to prevent entrance of light at this point. A shallow groove, d, is formed longitudinally in each side of each bar D, and each ot' such grooves is adapted to hug the. edge of a rib, F, secured to the outer edge Se of a bar, F, which closes the outer end or mouth of each plate-chamber B. Vhen either slide is pushed in to its place,the bar D springs over and hugs the rib E, and prevents accidental misplacement of the slide. The slide S5 may also be inserted either side outward,which is a matter of greater convenience. XVhen in a closed position, the inner edge of each bar F extends into the chamber B a short distance beyond the inner adjacent edge of the frame 9o A, in order to prevent escape ofthe sensitized plate, while to prevent rattle ot' suoli plate a curved platespring, e, is secured to each side of the partition B. Vhen the bar F is in its innermostposition,itprevents,asbeforestated, the-escape of the plate, and to prevent accidental movement ot' each bar F, l employ two removable plates or keys, fj', the inner ends e @einem of which abut against opposite ends of the conjoint ribs lil ll, be'l'ore named, while the outer ends of these keys extend behind abutments y g, formed by lugs 7iy h, secured to the outer corners of one end ot the frame A. So long as these keys/"f are in plaee the bars F F cannot be retraeted, and the sensitized plate Cannot eseape. `When it is desiredto remore or insert a plate, the keys j' j" are removed, which permits thebar F to be retracted. lt frequently happens that the dark-slides of plate-holders accidentally slip in their reeep taeles andadmitlighttotheplate-ehamber. By employing the bars D D, with theiroppositelydisposed grooves d d, and the ribs lfl ll to engage such grooves, accidental misplaoement or slipping ot' a plate is prevented. Ilo el'leetually prevent leakage of light to the interior of eaeli plate chamber between the outer boundary of eaeh opening,I groove the outer 'face ol' eaeh bar or gate F longitudinally, as shown at fz', and I iill this groove with plush or other material, which bears against the inner faee ofthe dark-slide.

I claiml. In Combination "with the frame A and partition, the adjustable bars F F, these barsl F closing the mouths Qt the lateAeh-amber, re-

speetively, and when in their in most positions extending into sueh chamber beyond the inner edge of the frame, substantially as stated.

2. In Combination with the frame A and the partition B, dividing such 'frame centrally ol' the adjustable bars or gates F F, the eentral ribs,l l Eupen sneh bars, and lthekeysff, operating with the said ribs Il Il, and the abutments f/ y, substantially as and for purposes stated. j

3. In Combination with eaeh dark-slide (l, the bar l), haring the grooves d in opposite sides, and the rib 1E,shaped to :lit said grooves, substantially as described.

el. In Combination with 4the f'ame A and partition B, the dark slides C (l with the grooyed bars D, the bars D with their ribs E, and adjustable with respect to the said frame and partition, and the keys fj', engaging at one end the said rib, and at the other the abn tinents .f/ g, all substantially as explained.

In testimony 'whereof I all'ix my signature in presenee of tiro witnesses.

Tl IOMAS HENRY A' LA'Ilt,

lVitnesses:

H. E. Lonen, E. A. G. RoULsroNn. 

